import {
    EventDispatcher,
    MOUSE,
    Quaternion,
    Spherical,
    TOUCH,
    Vector2,
    Vector3,
    Plane,
    Ray,
    MathUtils
} from 'three';

// OrbitControls performs orbiting, dollying (zooming), and panning.
// Unlike TrackballControls, it maintains the "up" direction object.up (+Y by default).
//
//    Orbit - left mouse / touch: one-finger move
//    Zoom - middle mouse, or mousewheel / touch: two-finger spread or squish
//    Pan - right mouse, or left mouse + ctrl/meta/shiftKey, or arrow keys / touch: two-finger move

const _changeEvent = { type: 'change' };
const _startEvent = { type: 'start' };
const _endEvent = { type: 'end' };
const _ray = new Ray();
const _plane = new Plane();
const TILT_LIMIT = Math.cos(70 * MathUtils.DEG2RAD);

/**@type {{[key:string]:((event:any)=>void)[]}} */
const eventMap = {};
class OrbitControls extends EventDispatcher {

    constructor(object,domElement) {

        super();

        let __preZoom = 1;

        this.object = object;
        this.domElement = domElement;
        this.domElement.style.touchAction = 'none'; // disable touch scroll

        // Set to false to disable this control
        this.enabled = true;

        // "target" sets the location of focus, where the object orbits around
        this.target = new Vector3();

        // Sets the 3D cursor (similar to Blender), from which the maxTargetRadius takes effect
        this.cursor = new Vector3();

        // How far you can dolly in and out ( PerspectiveCamera only )
        this.minDistance = 0;
        this.maxDistance = Infinity;

        // How far you can zoom in and out ( OrthographicCamera only )
        this.minZoom = 0;
        this.maxZoom = Infinity;

        // Limit camera target within a spherical area around the cursor
        this.minTargetRadius = 0;
        this.maxTargetRadius = Infinity;

        // How far you can orbit vertically, upper and lower limits.
        // Range is 0 to Math.PI radians.
        this.minPolarAngle = 0; // radians
        this.maxPolarAngle = Math.PI; // radians

        // How far you can orbit horizontally, upper and lower limits.
        // If set, the interval [ min, max ] must be a sub-interval of [ - 2 PI, 2 PI ], with ( max - min < 2 PI )
        this.minAzimuthAngle = - Infinity; // radians
        this.maxAzimuthAngle = Infinity; // radians

        // Set to true to enable damping (inertia)
        // If damping is enabled, you must call controls.update() in your animation loop
        this.enableDamping = false;
        this.dampingFactor = 0.05;

        // This option actually enables dollying in and out; left as "zoom" for backwards compatibility.
        // Set to false to disable zooming
        this.enableZoom = true;
        this.zoomSpeed = 1.0;

        this.enableDolly = true;

        // Set to false to disable rotating
        this.enableRotate = true;
        this.rotateSpeed = 1.0;

        // Set to false to disable panning
        this.enablePan = true;
        this.panSpeed = 1.0;
        this.screenSpacePanning = true; // if false, pan orthogonal to world-space direction camera.up
        this.keyPanSpeed = 7.0;	// pixels moved per arrow key push
        this.zoomToCursor = false;

        // Set to true to automatically rotate around the target
        // If auto-rotate is enabled, you must call controls.update() in your animation loop
        this.autoRotate = false;
        this.autoRotateSpeed = 2.0; // 30 seconds per orbit when fps is 60

        // The four arrow keys
        this.keys = { LEFT: 'ArrowLeft',UP: 'ArrowUp',RIGHT: 'ArrowRight',BOTTOM: 'ArrowDown' };

        // Mouse buttons
        this.mouseButtons = { LEFT: MOUSE.ROTATE,MIDDLE: MOUSE.DOLLY,RIGHT: MOUSE.PAN };

        // Touch fingers
        this.touches = { ONE: TOUCH.ROTATE,TWO: TOUCH.DOLLY_PAN };

        // for reset
        this.target0 = this.target.clone();
        this.position0 = this.object.position.clone();
        this.zoom0 = this.object.zoom;

        // the target DOM element for key events
        this._domElementKeyEvents = null;

        //
        // public methods
        //

        this.getPolarAngle = function () {

            return spherical.phi;

        };

        this.getAzimuthalAngle = function () {

            return spherical.theta;

        };

        this.getDistance = function () {

            return this.object.position.distanceTo(this.target);

        };

        this.listenToKeyEvents = function (domElement) {

            domElement.addEventListener('keydown',onKeyDown);
            this._domElementKeyEvents = domElement;

        };

        this.stopListenToKeyEvents = function () {

            this._domElementKeyEvents.removeEventListener('keydown',onKeyDown);
            this._domElementKeyEvents = null;

        };

        this.saveState = function () {

            scope.target0.copy(scope.target);
            scope.position0.copy(scope.object.position);
            scope.zoom0 = scope.object.zoom;

        };

        this.reset = function () {

            scope.target.copy(scope.target0);
            scope.object.position.copy(scope.position0);
            scope.object.zoom = scope.zoom0;

            scope.object.updateProjectionMatrix();
            scope.dispatchEvent(_changeEvent);

            scope.update();

            state = STATE.NONE;

        };

        // this method is exposed, but perhaps it would be better if we can make it private...
        this.update = function () {

            const offset = new Vector3();

            // so camera.up is the orbit axis
            const quat = new Quaternion().setFromUnitVectors(object.up,new Vector3(0,1,0));
            const quatInverse = quat.clone().invert();

            const lastPosition = new Vector3();
            const lastQuaternion = new Quaternion();
            const lastTargetPosition = new Vector3();

            const twoPI = 2 * Math.PI;

            return function update(deltaTime = null) {

                const position = scope.object.position;

                offset.copy(position).sub(scope.target);

                // rotate offset to "y-axis-is-up" space
                offset.applyQuaternion(quat);

                // angle from z-axis around y-axis
                spherical.setFromVector3(offset);

                if (scope.autoRotate && state === STATE.NONE) {

                    rotateLeft(getAutoRotationAngle(deltaTime));

                }

                if (scope.enableDamping) {

                    spherical.theta += sphericalDelta.theta * scope.dampingFactor;
                    spherical.phi += sphericalDelta.phi * scope.dampingFactor;

                } else {

                    spherical.theta += sphericalDelta.theta;
                    spherical.phi += sphericalDelta.phi;

                }

                // restrict theta to be between desired limits

                let min = scope.minAzimuthAngle;
                let max = scope.maxAzimuthAngle;

                if (isFinite(min) && isFinite(max)) {

                    if (min < - Math.PI) min += twoPI; else if (min > Math.PI) min -= twoPI;

                    if (max < - Math.PI) max += twoPI; else if (max > Math.PI) max -= twoPI;

                    if (min <= max) {

                        spherical.theta = Math.max(min,Math.min(max,spherical.theta));

                    } else {

                        spherical.theta = (spherical.theta > (min + max) / 2) ?
                            Math.max(min,spherical.theta) :
                            Math.min(max,spherical.theta);

                    }

                }

                // restrict phi to be between desired limits
                spherical.phi = Math.max(scope.minPolarAngle,Math.min(scope.maxPolarAngle,spherical.phi));

                spherical.makeSafe();


                // move target to panned location

                if (scope.enableDamping === true) {

                    scope.target.addScaledVector(panOffset,scope.dampingFactor);

                } else {

                    scope.target.add(panOffset);

                }

                // Limit the target distance from the cursor to create a sphere around the center of interest
                scope.target.sub(scope.cursor);
                scope.target.clampLength(scope.minTargetRadius,scope.maxTargetRadius);
                scope.target.add(scope.cursor);

                let zoomChanged = false;
                // adjust the camera position based on zoom only if we're not zooming to the cursor or if it's an ortho camera
                // we adjust zoom later in these cases
                if (scope.zoomToCursor && performCursorZoom || scope.object.isOrthographicCamera) {

                    spherical.radius = clampDistance(spherical.radius);

                } else {

                    const prevRadius = spherical.radius;
                    spherical.radius = clampDistance(spherical.radius * scale);
                    zoomChanged = prevRadius != spherical.radius;

                }

                offset.setFromSpherical(spherical);

                // rotate offset back to "camera-up-vector-is-up" space
                offset.applyQuaternion(quatInverse);

                position.copy(scope.target).add(offset);

                scope.object.lookAt(scope.target);

                if (scope.enableDamping === true) {

                    sphericalDelta.theta *= (1 - scope.dampingFactor);
                    sphericalDelta.phi *= (1 - scope.dampingFactor);

                    panOffset.multiplyScalar(1 - scope.dampingFactor);

                } else {

                    sphericalDelta.set(0,0,0);

                    panOffset.set(0,0,0);

                }

                // adjust camera position
                if (scope.zoomToCursor && performCursorZoom) {

                    let newRadius = null;
                    if (scope.object.isPerspectiveCamera) {

                        // move the camera down the pointer ray
                        // this method avoids floating point error
                        const prevRadius = offset.length();
                        newRadius = clampDistance(prevRadius * scale);

                        const radiusDelta = prevRadius - newRadius;
                        scope.object.position.addScaledVector(dollyDirection,radiusDelta);
                        scope.object.updateMatrixWorld();

                        zoomChanged = !!radiusDelta;

                    } else if (scope.object.isOrthographicCamera) {

                        // adjust the ortho camera position based on zoom changes
                        const mouseBefore = new Vector3(mouse.x,mouse.y,0);
                        mouseBefore.unproject(scope.object);

                        const prevZoom = scope.object.zoom;
                        scope.object.zoom = Math.max(scope.minZoom,Math.min(scope.maxZoom,scope.object.zoom / scale));
                        scope.object.updateProjectionMatrix();

                        zoomChanged = prevZoom !== scope.object.zoom;

                        const mouseAfter = new Vector3(mouse.x,mouse.y,0);
                        mouseAfter.unproject(scope.object);

                        scope.object.position.sub(mouseAfter).add(mouseBefore);
                        scope.object.updateMatrixWorld();

                        newRadius = offset.length();

                    } else {

                        console.warn('WARNING: OrbitControls.js encountered an unknown camera type - zoom to cursor disabled.');
                        scope.zoomToCursor = false;

                    }

                    // handle the placement of the target
                    if (newRadius !== null) {

                        if (this.screenSpacePanning) {

                            // position the orbit target in front of the new camera position
                            scope.target.set(0,0,- 1)
                                .transformDirection(scope.object.matrix)
                                .multiplyScalar(newRadius)
                                .add(scope.object.position);

                        } else {

                            // get the ray and translation plane to compute target
                            _ray.origin.copy(scope.object.position);
                            _ray.direction.set(0,0,- 1).transformDirection(scope.object.matrix);

                            // if the camera is 20 degrees above the horizon then don't adjust the focus target to avoid
                            // extremely large values
                            if (Math.abs(scope.object.up.dot(_ray.direction)) < TILT_LIMIT) {

                                object.lookAt(scope.target);

                            } else {

                                _plane.setFromNormalAndCoplanarPoint(scope.object.up,scope.target);
                                _ray.intersectPlane(_plane,scope.target);

                            }

                        }

                    }

                } else if (scope.object.isOrthographicCamera) {

                    const prevZoom = scope.object.zoom;
                    scope.object.zoom = Math.max(scope.minZoom,Math.min(scope.maxZoom,scope.object.zoom / scale));

                    if (prevZoom !== scope.object.zoom) {

                        scope.object.updateProjectionMatrix();
                        zoomChanged = true;

                    }

                    zoomChanged = prevZoom !== __preZoom;

                    __preZoom = prevZoom;

                }

                scale = 1;
                performCursorZoom = false;

                // update condition is:
                // min(camera displacement, camera rotation in radians)^2 > EPS
                // using small-angle approximation cos(x/2) = 1 - x^2 / 8

                if (zoomChanged ||
                    lastPosition.distanceToSquared(scope.object.position) > EPS ||
                    8 * (1 - lastQuaternion.dot(scope.object.quaternion)) > EPS ||
                    lastTargetPosition.distanceToSquared(scope.target) > EPS) {

                    scope.dispatchEvent(_changeEvent);

                    lastPosition.copy(scope.object.position);
                    lastQuaternion.copy(scope.object.quaternion);
                    lastTargetPosition.copy(scope.target);

                    return true;

                }

                return false;

            };

        }();

        this.dispose = function () {

            scope.domElement.removeEventListener('contextmenu',onContextMenu);

            scope.domElement.removeEventListener('pointerdown',onPointerDown);
            scope.domElement.removeEventListener('pointercancel',onPointerUp);
            scope.domElement.removeEventListener('wheel',onMouseWheel);

            scope.domElement.removeEventListener('pointermove',onPointerMove);
            scope.domElement.removeEventListener('pointerup',onPointerUp);

            const document = scope.domElement.getRootNode(); // offscreen canvas compatibility

            document.removeEventListener('keydown',interceptControlDown,{ capture: true });

            if (scope._domElementKeyEvents !== null) {

                scope._domElementKeyEvents.removeEventListener('keydown',onKeyDown);
                scope._domElementKeyEvents = null;

            }

            Reflect.ownKeys(eventMap).forEach(key => {

                const listeners = eventMap[key];

                if (listeners) {

                    listeners.forEach(listener => {

                        scope.removeEventListener(key,listener);

                    });

                    eventMap[key].length = 0;

                }

            });

            //scope.dispatchEvent( { type: 'dispose' } ); // should this be added here?

        };

        this.init = function () {

            scope.domElement.addEventListener('contextmenu',onContextMenu);

            scope.domElement.addEventListener('pointerdown',onPointerDown);
            scope.domElement.addEventListener('pointercancel',onPointerUp);
            scope.domElement.addEventListener('wheel',onMouseWheel);

            const document = scope.domElement.getRootNode(); // offscreen canvas compatibility

            document.addEventListener('keydown',interceptControlDown,{ passive: true,capture: true });

        };

        //
        // internals
        //

        const scope = this;

        const STATE = {
            NONE: - 1,
            ROTATE: 0,
            DOLLY: 1,
            PAN: 2,
            TOUCH_ROTATE: 3,
            TOUCH_PAN: 4,
            TOUCH_DOLLY_PAN: 5,
            TOUCH_DOLLY_ROTATE: 6
        };

        let state = STATE.NONE;

        const EPS = 0.000001;

        // current position in spherical coordinates
        const spherical = new Spherical();
        const sphericalDelta = new Spherical();

        let scale = 1;
        const panOffset = new Vector3();

        const rotateStart = new Vector2();
        const rotateEnd = new Vector2();
        const rotateDelta = new Vector2();

        const panStart = new Vector2();
        const panEnd = new Vector2();
        const panDelta = new Vector2();

        const dollyStart = new Vector2();
        const dollyEnd = new Vector2();
        const dollyDelta = new Vector2();

        const dollyDirection = new Vector3();
        const mouse = new Vector2();
        let performCursorZoom = false;

        const pointers = [];
        const pointerPositions = {};

        let controlActive = false;

        function getAutoRotationAngle(deltaTime) {

            if (deltaTime !== null) {

                return (2 * Math.PI / 60 * scope.autoRotateSpeed) * deltaTime;

            } else {

                return 2 * Math.PI / 60 / 60 * scope.autoRotateSpeed;

            }

        }

        function getZoomScale(delta) {

            const normalizedDelta = Math.abs(delta * 0.01);
            return Math.pow(0.95,scope.zoomSpeed * normalizedDelta);

        }

        function rotateLeft(angle) {

            sphericalDelta.theta -= angle;

        }

        function rotateUp(angle) {

            sphericalDelta.phi -= angle;

        }

        const panLeft = function () {

            const v = new Vector3();

            return function panLeft(distance,objectMatrix) {

                v.setFromMatrixColumn(objectMatrix,0); // get X column of objectMatrix
                v.multiplyScalar(- distance);

                panOffset.add(v);

            };

        }();

        const panUp = function () {

            const v = new Vector3();

            return function panUp(distance,objectMatrix) {

                if (scope.screenSpacePanning === true) {

                    v.setFromMatrixColumn(objectMatrix,1);

                } else {

                    v.setFromMatrixColumn(objectMatrix,0);
                    v.crossVectors(scope.object.up,v);

                }

                v.multiplyScalar(distance);

                panOffset.add(v);

            };

        }();

        // deltaX and deltaY are in pixels; right and down are positive
        const pan = function () {

            const offset = new Vector3();

            return function pan(deltaX,deltaY) {

                const element = scope.domElement;

                if (scope.object.isPerspectiveCamera) {

                    // perspective
                    const position = scope.object.position;
                    offset.copy(position).sub(scope.target);
                    let targetDistance = offset.length();

                    // half of the fov is center to top of screen
                    targetDistance *= Math.tan((scope.object.fov / 2) * Math.PI / 180.0);

                    // we use only clientHeight here so aspect ratio does not distort speed
                    panLeft(2 * deltaX * targetDistance / element.clientHeight,scope.object.matrix);
                    panUp(2 * deltaY * targetDistance / element.clientHeight,scope.object.matrix);

                } else if (scope.object.isOrthographicCamera) {

                    // orthographic
                    panLeft(deltaX * (scope.object.right - scope.object.left) / scope.object.zoom / element.clientWidth,scope.object.matrix);
                    panUp(deltaY * (scope.object.top - scope.object.bottom) / scope.object.zoom / element.clientHeight,scope.object.matrix);

                } else {

                    // camera neither orthographic nor perspective
                    console.warn('WARNING: OrbitControls.js encountered an unknown camera type - pan disabled.');
                    scope.enablePan = false;

                }

            };

        }();

        function dollyOut(dollyScale) {

            if (scope.object.isPerspectiveCamera || scope.object.isOrthographicCamera) {

                scale /= dollyScale;

            } else {

                console.warn('WARNING: OrbitControls.js encountered an unknown camera type - dolly/zoom disabled.');
                scope.enableZoom = false;

            }

        }

        function dollyIn(dollyScale) {

            if (scope.object.isPerspectiveCamera || scope.object.isOrthographicCamera) {

                scale *= dollyScale;

            } else {

                console.warn('WARNING: OrbitControls.js encountered an unknown camera type - dolly/zoom disabled.');
                scope.enableZoom = false;

            }

        }

        function updateZoomParameters(x,y) {

            if (!scope.zoomToCursor) {

                return;

            }

            performCursorZoom = true;

            const rect = scope.domElement.getBoundingClientRect();
            const dx = x - rect.left;
            const dy = y - rect.top;
            const w = rect.width;
            const h = rect.height;

            mouse.x = (dx / w) * 2 - 1;
            mouse.y = - (dy / h) * 2 + 1;

            dollyDirection.set(mouse.x,mouse.y,1).unproject(scope.object).sub(scope.object.position).normalize();

        }

        function clampDistance(dist) {

            return Math.max(scope.minDistance,Math.min(scope.maxDistance,dist));

        }

        //
        // event callbacks - update the object state
        //

        function handleMouseDownRotate(event) {

            rotateStart.set(event.clientX,event.clientY);

        }

        function handleMouseDownDolly(event) {

            updateZoomParameters(event.clientX,event.clientX);
            dollyStart.set(event.clientX,event.clientY);

        }

        function handleMouseDownPan(event) {

            panStart.set(event.clientX,event.clientY);

        }

        function handleMouseMoveRotate(event) {

            rotateEnd.set(event.clientX,event.clientY);

            rotateDelta.subVectors(rotateEnd,rotateStart).multiplyScalar(scope.rotateSpeed);

            const element = scope.domElement;

            rotateLeft(2 * Math.PI * rotateDelta.x / element.clientHeight); // yes, height

            rotateUp(2 * Math.PI * rotateDelta.y / element.clientHeight);

            rotateStart.copy(rotateEnd);

            scope.update();

        }

        function handleMouseMoveDolly(event) {

            dollyEnd.set(event.clientX,event.clientY);

            dollyDelta.subVectors(dollyEnd,dollyStart);

            if (dollyDelta.y > 0) {

                dollyOut(getZoomScale(dollyDelta.y));

            } else if (dollyDelta.y < 0) {

                dollyIn(getZoomScale(dollyDelta.y));

            }

            dollyStart.copy(dollyEnd);

            scope.update();

        }

        function handleMouseMovePan(event) {

            panEnd.set(event.clientX,event.clientY);

            panDelta.subVectors(panEnd,panStart).multiplyScalar(scope.panSpeed);

            pan(panDelta.x,panDelta.y);

            panStart.copy(panEnd);

            scope.update();

        }

        function handleMouseWheel(event) {

            updateZoomParameters(event.clientX,event.clientY);

            if (event.deltaY < 0) {

                dollyIn(getZoomScale(event.deltaY));

            } else if (event.deltaY > 0) {

                dollyOut(getZoomScale(event.deltaY));

            }

            scope.update();

        }

        function handleKeyDown(event) {

            let needsUpdate = false;

            switch (event.code) {

                case scope.keys.UP:

                    if (event.ctrlKey || event.metaKey || event.shiftKey) {

                        rotateUp(2 * Math.PI * scope.rotateSpeed / scope.domElement.clientHeight);

                    } else {

                        pan(0,scope.keyPanSpeed);

                    }

                    needsUpdate = true;
                    break;

                case scope.keys.BOTTOM:

                    if (event.ctrlKey || event.metaKey || event.shiftKey) {

                        rotateUp(- 2 * Math.PI * scope.rotateSpeed / scope.domElement.clientHeight);

                    } else {

                        pan(0,- scope.keyPanSpeed);

                    }

                    needsUpdate = true;
                    break;

                case scope.keys.LEFT:

                    if (event.ctrlKey || event.metaKey || event.shiftKey) {

                        rotateLeft(2 * Math.PI * scope.rotateSpeed / scope.domElement.clientHeight);

                    } else {

                        pan(scope.keyPanSpeed,0);

                    }

                    needsUpdate = true;
                    break;

                case scope.keys.RIGHT:

                    if (event.ctrlKey || event.metaKey || event.shiftKey) {

                        rotateLeft(- 2 * Math.PI * scope.rotateSpeed / scope.domElement.clientHeight);

                    } else {

                        pan(- scope.keyPanSpeed,0);

                    }

                    needsUpdate = true;
                    break;

            }

            if (needsUpdate) {

                // prevent the browser from scrolling on cursor keys
                event.preventDefault();

                scope.update();

            }


        }

        function handleTouchStartRotate(event) {

            if (pointers.length === 1) {

                rotateStart.set(event.pageX,event.pageY);

            } else {

                const position = getSecondPointerPosition(event);

                const x = 0.5 * (event.pageX + position.x);
                const y = 0.5 * (event.pageY + position.y);

                rotateStart.set(x,y);

            }

        }

        function handleTouchStartPan(event) {

            if (pointers.length === 1) {

                panStart.set(event.pageX,event.pageY);

            } else {

                const position = getSecondPointerPosition(event);

                const x = 0.5 * (event.pageX + position.x);
                const y = 0.5 * (event.pageY + position.y);

                panStart.set(x,y);

            }

        }

        function handleTouchStartDolly(event) {

            const position = getSecondPointerPosition(event);

            const dx = event.pageX - position.x;
            const dy = event.pageY - position.y;

            const distance = Math.sqrt(dx * dx + dy * dy);

            dollyStart.set(0,distance);

        }

        function handleTouchStartDollyPan(event) {

            if (scope.enableZoom) handleTouchStartDolly(event);

            if (scope.enablePan) handleTouchStartPan(event);

        }

        function handleTouchStartDollyRotate(event) {

            if (scope.enableZoom) handleTouchStartDolly(event);

            if (scope.enableRotate) handleTouchStartRotate(event);

        }

        function handleTouchMoveRotate(event) {

            if (pointers.length == 1) {

                rotateEnd.set(event.pageX,event.pageY);

            } else {

                const position = getSecondPointerPosition(event);

                const x = 0.5 * (event.pageX + position.x);
                const y = 0.5 * (event.pageY + position.y);

                rotateEnd.set(x,y);

            }

            rotateDelta.subVectors(rotateEnd,rotateStart).multiplyScalar(scope.rotateSpeed);

            const element = scope.domElement;

            rotateLeft(2 * Math.PI * rotateDelta.x / element.clientHeight); // yes, height

            rotateUp(2 * Math.PI * rotateDelta.y / element.clientHeight);

            rotateStart.copy(rotateEnd);

        }

        function handleTouchMovePan(event) {

            if (pointers.length === 1) {

                panEnd.set(event.pageX,event.pageY);

            } else {

                const position = getSecondPointerPosition(event);

                const x = 0.5 * (event.pageX + position.x);
                const y = 0.5 * (event.pageY + position.y);

                panEnd.set(x,y);

            }

            panDelta.subVectors(panEnd,panStart).multiplyScalar(scope.panSpeed);

            pan(panDelta.x,panDelta.y);

            panStart.copy(panEnd);

        }

        function handleTouchMoveDolly(event) {

            const position = getSecondPointerPosition(event);

            const dx = event.pageX - position.x;
            const dy = event.pageY - position.y;

            const distance = Math.sqrt(dx * dx + dy * dy);

            dollyEnd.set(0,distance);

            dollyDelta.set(0,Math.pow(dollyEnd.y / dollyStart.y,scope.zoomSpeed));

            dollyOut(dollyDelta.y);

            dollyStart.copy(dollyEnd);

            const centerX = (event.pageX + position.x) * 0.5;
            const centerY = (event.pageY + position.y) * 0.5;

            updateZoomParameters(centerX,centerY);

        }

        function handleTouchMoveDollyPan(event) {

            if (scope.enableZoom) handleTouchMoveDolly(event);

            if (scope.enablePan) handleTouchMovePan(event);

        }

        function handleTouchMoveDollyRotate(event) {

            if (scope.enableZoom) handleTouchMoveDolly(event);

            if (scope.enableRotate) handleTouchMoveRotate(event);

        }

        //
        // event handlers - FSM: listen for events and reset state
        //

        function onPointerDown(event) {

            if (scope.enabled === false) return;

            mouse.set(event.clientX,event.clientY);
            scope.mousedown_moving = false;

            if (pointers.length === 0) {

                // todo 注释这一行，让 CSS3D CSS2D 元素可以监听 click 事件，但是在界面外将失去控制。
                // scope.domElement.setPointerCapture(event.pointerId);

                scope.domElement.addEventListener('pointermove',onPointerMove);
                scope.domElement.addEventListener('pointerup',onPointerUp);

            }

            //

            if (isTrackingPointer(event)) return;

            //

            addPointer(event);

            if (event.pointerType === 'touch') {

                onTouchStart(event);

            } else {

                onMouseDown(event);

            }

        }

        function onPointerMove(event) {

            if (scope.enabled === false) return;

            if (!scope.mousedown_moving && (mouse.x !== event.clientX || mouse.y !== event.clientY)) {

                scope.mousedown_moving = true;

                if (state === STATE.ROTATE || state === STATE.PAN) {

                    scope.dispatchEvent(_startEvent);

                }

            }

            if (event.pointerType === 'touch') {

                onTouchMove(event);

            } else {

                onMouseMove(event);

            }

        }

        function onPointerUp(event) {

            removePointer(event);

            switch (pointers.length) {

                case 0:

                    scope.domElement.releasePointerCapture(event.pointerId);

                    scope.domElement.removeEventListener('pointermove',onPointerMove);
                    scope.domElement.removeEventListener('pointerup',onPointerUp);

                    if (state === STATE.ROTATE || state === STATE.PAN) {

                        state = STATE.NONE;

                        if (mouse.x === event.clientX && mouse.y === event.clientY) return;

                        scope.dispatchEvent(_endEvent);

                    }

                    state = STATE.NONE;

                    break;

                case 1:

                    const pointerId = pointers[0];
                    const position = pointerPositions[pointerId];

                    // minimal placeholder event - allows state correction on pointer-up
                    onTouchStart({ pointerId: pointerId,pageX: position.x,pageY: position.y });

                    break;

            }

        }

        function onMouseDown(event) {

            mouse.set(event.clientX,event.clientY);

            let mouseAction;

            switch (event.button) {

                case 0:

                    mouseAction = scope.mouseButtons.LEFT;
                    break;

                case 1:

                    mouseAction = scope.mouseButtons.MIDDLE;
                    break;

                case 2:

                    mouseAction = scope.mouseButtons.RIGHT;
                    break;

                default:

                    mouseAction = - 1;

            }

            switch (mouseAction) {

                case MOUSE.DOLLY:

                    if (scope.enableZoom === false) return;

                    handleMouseDownDolly(event);

                    state = STATE.DOLLY;

                    break;

                case MOUSE.ROTATE:

                    if (event.ctrlKey || event.metaKey || event.shiftKey) {

                        if (scope.enablePan === false) return;

                        handleMouseDownPan(event);

                        state = STATE.PAN;

                    } else {

                        if (scope.enableRotate === false) return;

                        handleMouseDownRotate(event);

                        state = STATE.ROTATE;

                    }

                    break;

                case MOUSE.PAN:

                    if (event.ctrlKey || event.metaKey || event.shiftKey) {

                        if (scope.enableRotate === false) return;

                        handleMouseDownRotate(event);

                        state = STATE.ROTATE;

                    } else {

                        if (scope.enablePan === false) return;

                        handleMouseDownPan(event);

                        state = STATE.PAN;

                    }

                    break;

                default:

                    state = STATE.NONE;

            }

        }

        function onMouseMove(event) {

            switch (state) {

                case STATE.ROTATE:

                    if (scope.enableRotate === false) return;

                    handleMouseMoveRotate(event);

                    break;

                case STATE.DOLLY:

                    if (scope.enableDolly === false) return;

                    handleMouseMoveDolly(event);

                    break;

                case STATE.PAN:

                    if (scope.enablePan === false) return;

                    handleMouseMovePan(event);

                    break;

            }

        }

        function onMouseWheel(event) {

            if (scope.enabled === false || scope.enableZoom === false || state !== STATE.NONE) return;

            event.preventDefault();

            clearTimeout(scope.mousewheelTimer);

            if (!scope.isWheeling) {
                scope.dispatchEvent(_startEvent);
                scope.isWheeling = true;
            }

            handleMouseWheel(customWheelEvent(event));

            scope.mousewheelTimer = setTimeout(() => {
                scope.dispatchEvent(_endEvent);
                scope.isWheeling = false;
            },400);

        }

        function customWheelEvent(event) {

            const mode = event.deltaMode;

            // minimal wheel event altered to meet delta-zoom demand
            const newEvent = {
                clientX: event.clientX,
                clientY: event.clientY,
                deltaY: event.deltaY,
            };

            switch (mode) {

                case 1: // LINE_MODE
                    newEvent.deltaY *= 16;
                    break;

                case 2: // PAGE_MODE
                    newEvent.deltaY *= 100;
                    break;

            }

            // detect if event was triggered by pinching
            if (event.ctrlKey && !controlActive) {

                newEvent.deltaY *= 10;

            }

            return newEvent;

        }

        function interceptControlDown(event) {

            if (event.key === 'Control') {

                controlActive = true;


                const document = scope.domElement.getRootNode(); // offscreen canvas compatibility

                document.addEventListener('keyup',interceptControlUp,{ passive: true,capture: true });

            }

        }

        function interceptControlUp(event) {

            if (event.key === 'Control') {

                controlActive = false;


                const document = scope.domElement.getRootNode(); // offscreen canvas compatibility

                document.removeEventListener('keyup',interceptControlUp,{ passive: true,capture: true });

            }

        }

        function onKeyDown(event) {

            if (scope.enabled === false || scope.enablePan === false) return;

            handleKeyDown(event);

        }

        function onTouchStart(event) {

            trackPointer(event);

            switch (pointers.length) {

                case 1:

                    switch (scope.touches.ONE) {

                        case TOUCH.ROTATE:

                            if (scope.enableRotate === false) return;

                            handleTouchStartRotate(event);

                            state = STATE.TOUCH_ROTATE;

                            break;

                        case TOUCH.PAN:

                            if (scope.enablePan === false) return;

                            handleTouchStartPan(event);

                            state = STATE.TOUCH_PAN;

                            break;

                        default:

                            state = STATE.NONE;

                    }

                    break;

                case 2:

                    switch (scope.touches.TWO) {

                        case TOUCH.DOLLY_PAN:

                            if (scope.enableZoom === false && scope.enablePan === false) return;

                            handleTouchStartDollyPan(event);

                            state = STATE.TOUCH_DOLLY_PAN;

                            break;

                        case TOUCH.DOLLY_ROTATE:

                            if (scope.enableZoom === false && scope.enableRotate === false) return;

                            handleTouchStartDollyRotate(event);

                            state = STATE.TOUCH_DOLLY_ROTATE;

                            break;

                        default:

                            state = STATE.NONE;

                    }

                    break;

                default:

                    state = STATE.NONE;

            }



        }

        function onTouchMove(event) {

            trackPointer(event);

            switch (state) {

                case STATE.TOUCH_ROTATE:

                    if (scope.enableRotate === false) return;

                    handleTouchMoveRotate(event);

                    scope.update();

                    break;

                case STATE.TOUCH_PAN:

                    if (scope.enablePan === false) return;

                    handleTouchMovePan(event);

                    scope.update();

                    break;

                case STATE.TOUCH_DOLLY_PAN:

                    if (scope.enableZoom === false && scope.enablePan === false) return;

                    handleTouchMoveDollyPan(event);

                    scope.update();

                    break;

                case STATE.TOUCH_DOLLY_ROTATE:

                    if (scope.enableZoom === false && scope.enableRotate === false) return;

                    handleTouchMoveDollyRotate(event);

                    scope.update();

                    break;

                default:

                    state = STATE.NONE;

            }

        }

        function onContextMenu(event) {

            if (scope.enabled === false) return;

            event.preventDefault();

        }

        function addPointer(event) {

            pointers.push(event.pointerId);

        }

        function removePointer(event) {

            delete pointerPositions[event.pointerId];

            for (let i = 0; i < pointers.length; i++) {

                if (pointers[i] == event.pointerId) {

                    pointers.splice(i,1);
                    return;

                }

            }

        }

        function isTrackingPointer(event) {

            for (let i = 0; i < pointers.length; i++) {

                if (pointers[i] == event.pointerId) return true;

            }

            return false;

        }

        function trackPointer(event) {

            let position = pointerPositions[event.pointerId];

            if (position === undefined) {

                position = new Vector2();
                pointerPositions[event.pointerId] = position;

            }

            position.set(event.pageX,event.pageY);

        }

        function getSecondPointerPosition(event) {

            const pointerId = (event.pointerId === pointers[0]) ? pointers[1] : pointers[0];

            return pointerPositions[pointerId];

        }

        //

        scope.domElement.addEventListener('contextmenu',onContextMenu);

        scope.domElement.addEventListener('pointerdown',onPointerDown);
        scope.domElement.addEventListener('pointercancel',onPointerUp);
        scope.domElement.addEventListener('wheel',onMouseWheel,{ passive: false });

        const document = scope.domElement.getRootNode(); // offscreen canvas compatibility

        document.addEventListener('keydown',interceptControlDown,{ passive: true,capture: true });

        // force an update at start

        this.update();

    }

    /**
     * 添加控制器的事件监听
     * @param {"change"|"start"|"end"} type
     * @param {(event)=>void} listener
     */
    addEventListener(type,listener) {

        const events = eventMap[type];

        if (!events) {

            eventMap[type] = [listener];

            super.addEventListener(type,listener);

        } else {

            if (events.indexOf(listener) === -1) {

                super.addEventListener(type,listener);

            }

        }

    }

    /**
     * 移除控制器的事件监听
     * @param {"change"|"start"|"end"} type
     * @param {(event)=>void} listener
     */
    removeEventListener(type,listener) {

        const events = eventMap[type];

        if (events) {

            const index = events.indexOf(listener);

            if (index !== -1) {

                events.splice(index,1);

                super.removeEventListener(type,listener);

            }

        }

    }

}

export { OrbitControls };
